A method and an arrangement for controlling the output power of a drive unit of a motor vehicle are disclosed in U.S. patent application Ser. No. 08/050,085, filed Apr. 28, 1993, now abandoned. Here, for the purpose of controlling the output power of a drive unit, a drive torque desired value is determined in dependence upon the driver command and, while computing a motor torque desired value, the motor torque is adjusted by influencing the power parameters of the motor for preparing an output torque corresponding to the desired value of the output torque. The motor torque desired value is determined from a characteristic field on the basis of the transmission ratio of the drive train (gear ratio of the transmission per se), of output torque desired value and of the measured output rpm. The computation of the desired motor torque is performed in that the output torque is made available independently of the gear stage into which the transmission has been shifted in accordance with the driver's command.
The following situation is presented for an automatic transmission having a converter having a controllable converter clutch (lockup clutch). The desired value of the output torque is determined from the output rpm and the accelerator pedal position and requires a certain desired torque at the transmission end of the converter (turbine wheel) in dependence upon the gear stage into which the transmission has been shifted. To obtain this desired turbine torque, a specific desired torque is required at the converter input (pump wheel) depending upon the adjusted torque transmission of the converter. The desired torque is that torque which is presented by the motor. Accordingly, and in order to obtain an output torque independently of the gear stage into which the transmission has been shifted and independently of the state of the converter, the torque transmission of the converter must be considered when determining the desired torque.